Step 2: Wiring & Assembly

Step 3: Using your Solar Boombox

Larger solar panels require charging circuitry to regulate the charge current and protect the battery from overcharging. Our solar panel is small enou...

You can construct a solar powered boombox for as little as $75

Combine a small, energy efficient digital amplifier, cheap bookshelf speakers, batteries, a small solar panel, and your MP3 player as a source.

Fasten everything together, add a handle, and take it on the road!

This project makes for a fun, easy solar project, that will help you learn about how solar panel, and audio systems operate.

Assembly has been simplified as much as possible, with a very high quality product as the end result.

Possible applications-

iPod or Mp3 amplifier

"Off grid" remote or cabin audiophile system

Third world use

Eco friendly sound system for outdoor events

Science fair or educational project

Jobsite radio and tool battery charger

Laptop amplifier for music and movies

The Sonic Impact digital amplifier has been raved about by audiophiles. It has the added benefit of using less electricity than a conventional solid state amplifier, which makes the battery last longer, and the required solar panel smaller.
It is capable of driving most home stereo speakers, so feel free to try it with any speakers you may have on hand. The results may surprise you!
Some speakers are more efficient than others and will play louder given the same input.

*Sonic Impact fans note*

A Sonic Impact amplifier ($30) will run directly off of a single Harbor Freight car charging solar panel($10-20) without a battery.
I offer no guarantees here, but in July Wisconsin sun, an unmodified SI amp was connected directly to the solar panel (a stock SINGLE Harbor Freight unit) and speakers. I did this repeatedly with no problems, other than that the music stops when clouds interfere, or the panel is shaded.

THIS MAKES A GREAT DEMONSTRATION!

The reason this is remarkable is that the voltage of the panel is over the maximum the amp is supposed to take. The load presented by the amp, draws the voltage down before the amp is damaged.
I have tested this extensively, but you try this at your own risk!

A more powerful panel, such as the double unit we use on the DelSol will be more likely to produce enough current to damage the amp.
I later modified the amplifier to improve the bass, and it required more current than the single panel provided.

Hey I am putting my boombox together. I'm using the recommended amp. First off can you briefly explain to me the series/parallel relationship between the three parts (battery, panel, amp)? Just one more thing. I'm using the led acid 12V 5.0 Ah battery. The recommended charging voltages for the battery says around 14-15V, but the panel puts out around 24V. Should I knock down the panel voltage or does it not matter?

The fifth picture under "Step 2 Wiring and Assembly" shows a simple schematic.You don't have to worry about the higher voltage of the solar panel, if it isn't significantly larger than the one I used (1.5 Watts). Just don't connect the solar panel to the amp without the battery being connected first.The battery will draw down the voltage of the panel, A small solar circuit such as this one can get by without a charge controller.Good luck!

It's a 1N4001 type.Available here-http://www.adafruit.com/products/755Most electronic devices have these inside, if you want to salvage one.Just pick one that looks like the picture, don't worry about exact part number.I'm glad you're enjoying the boombox!

Hello i know this is an old thread but i am building my own solar powered boom-box .I am using a Chinese Lepai T2020 amp , a 3w solar panel,pioneer Dual-Cone TS-1001i Speakers .will be incorporating a cigarette lighter plug that converts into 2 usb ports to charge phone and mp3 player.

now all i need is a battery and have been searching around for what type i can use.

am trying to keep the weight as low as possible so i don't need a heavy car battery but was wondering what is best for my setup?want to keep the boom box in the windowsill so i can charge my phone on a daily base .

am quite capable of soldering etc. .

so should i go for something like this and wire 10 of them to make my own battery packhttp://www.amazon.co.uk/Duracell-Supreme-2450mAh-Rechargeable-Batteries/dp/B0031OE6LG/ref=sr_1_1?ie=UTF8&qid=1288354114&sr=8-1or should i get a lead acid one like thishttp://www.amazon.co.uk/NP3-3-12-Ultramax-Rechargeable-Lead-Acid-Battery/dp/B002TW74P6/ref=wl_it_dp_o?ie=UTF8&coliid=I20SQT4IMYV1A6&colid=SO6O03Z0DRVD

am a bit lost in the whole battery thing so any help is much appreciated.

I really like my 10 aa NIMH pack the best. There are tutorials online explaining how to solder batteries together successfully, and assemble them into packs.The batteries you've linked to should work fine.

There's also this holder-http://www.maplin.co.uk/Module.aspx?ModuleNo=31427&OrderCode=RK45Y-if building the pack is too much trouble.

Thanks a bunch for this project. I used the 2x15 amp from Sure Electronics and some 10 watt RMS speakers I found cheap on Ebay. I built a pine box and hard wired it all together. Sure, it ways 30+ lbs, but it's loud. If anybody is just starting this project today (5/8/2010) you can find some Kricket 5" 10 watt RMS speakers on EBAY for about $25.

I would like to do the same thing here... except instead of building a box i am thinking about using a coleman or igloo cooler... with a Car Battery also using a Car/Marine Stereo and Speakers... I go on a lot of Tubing Trips in the summer and would like the best possible waterproof setup lemme know if you have any other suggestions as to what i can do.

There are other plans for cooler boomboxes online you can look at for inspiration.

my suggestions-

1. Many waterways ban glass. Look for a solar panel with no glass, they are available. Try marine sources. Some have a metal backing plate, some have circuit board material, some are flexible and roll up. One cheap source might be to gang together a bunch of garden light solar panels. http://www.allelectronics.com/make-a-store/item/SPL-61/SOLAR-CELL-60MM-X-60MM-X2MM/-/1.html http://www.jamestowndistributors.com/userportal/show_product.do?pid=52241&familyName=PowerFilm+Rollable+Solar+Chargers http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/424480/377%20710/0/solar/Primary%20Search/mode%20matchallpartial/0/0?N=377%20710&Ne=0&Ntt=solar&Ntk=Primary%20Search&Ntx=mode%20matchallpartial&Nao=0&Ns=0&keyword=solar&isLTokenURL=true&storeNum=5002&subdeptNum=9&classNum=592

2. You might not need a full size car battery, I'd try a garden tractor/motorcycle battery, or better yet, a large SLA computer power back up battery. Try Ebay.

3. Think about how you will use it. It might be easier to have the battery and solar panel removable so that you aren't leaving your whole stereo out to charge where it could get stolen or rained on.

as an fyi, parts express does sell a solar charger similar to the one specified (www.parts-express.com/pe/showdetl.cfm) but its twice as expensive. however, if you pick up the amp and batteries from parts express too you can just make the $100 free shipping, but the increase in price almost cancels it out. check the prices and figure out which is cheapest with shipping

I love this idea for our RV trips. I was wondering if a 12v auto plug (male) could be added and used with a Car battery. I have a 12v outlet (female) on the outside of my trailer and it would be nice to be able to hook up while outside in the evening. Would a 12v deep cycle marine battery cause damage to the amp (dayton) and if so what would be needed to protect it. If anyone has any ideas I would appreciate a scematic of some sort as I am a little green to electornics.

Yes, it also allows you to use multiple batteries. Personally, I find it most convenient to be able to separate the battery, solar panel, and boombox. This also allows me to charge the battery without having to leave the boombox out in the weather. You can hardwire everything, but I think most people will appreciate being able to separate the components. The plug/jack also helps avoid the possibility of connecting two power sources in series and frying the amp.

Wondering why I couldn't use a small (25 w.p.c. or so) car amp or eq/ booster to push a pair of 6x9's. I would of course use a 12v s.l.a. battery and a solar panel to recharge. Would either amp or eq be too inefficient voltage wise???

This will work, but is less efficient and would be better paired with a larger battery and solar panel. The beauty of my system is that the energy efficiency of the amplifier allows you to use a smaller solar panel/battery and still have a powerful system in a small package. I encourage you to experiment with whatever is on hand!

Pekar, one more question for ya. Just about got my system built, but I wanted to see if a piece of plexiglass layed over a solar panel for protection would do more harm than good ? Will it reflect light enough to not let the panel be as efficient as it would without it? Thanks for your reply.

Have wanted to do this for some time, so appreciate your work on this. I have the T-Amp and two Polk Audio DB650 car speakers which are very efficient and nice sounding. Also have a Creative MuVo2 FM 5gb which requires a 5v input In order to power the system for a good (long) amount of time at volume and under less than ideal solar conditions, I want to upgrade the solar panel and battery. Am looking at a 12v, 10W panel charging a 4.5ah lead acid 12v battery. Will I need a solar controller for this? Can the T-Amp run directly off the battery or is some sort of voltage regulator needed? Finally... can somebody suggest a DIY design for the car audio speakers to "tune" the sound? I'd like to make this enclosure from balsa wood backed by XPS (Dow Styrofoam) insulation with the balsa on the inside. Any thoughts/ help is appreciated!

a solar panel that large would overcharge a small battery very fast. so you will definitely want a charge controller. I would also suggest a larger battery 7 - 12 Ah. make sure that the output current from the panel is not over the max charge current of your battery.

Batteries can take up to 1/10 of their mAh rating and safely dissipate this as heat. In your case a solar panel could put out a maximum of 450 ma without requiring a charge controller. Your 10 watt panel is probably too large for that small battery.

Thx 4 the info. I want a system that can cleanly handle less than full sun. Ur in Badgerland, which has pretty much the same climate as me in Gopherland (MN.) When those big cumulus clouds come and go, I still want the tunes. I hooked up a solar panel in my Jetta (VW) and I've got a VW solar panel in there. (Max Power: 3.2 watts, Voltage @ Max Power; 18.8 Volts, Current @ Max Power: 170mAmps, 42 cells) Virtually every panel I've seen listed as 12V has 36 cells. This one has 42. When I plug the T-amp into this panel and turn the amp on, there is 1/2 second of sound, then nothing. This happens repeatedly. I'm thinking the voltage is too high and causing the T-Amp to clip out. When I put 8 NiMh AA cells in the T-Amp, it cranks out the sound. That's 9V. This is a lot more. I'm driving Polk Audio DB650 car speakers. Do you see any way to make this particular panel work? Could I hook it up to a 4ah battery and then plug the T-Amp onto the battery posts? Or will this setup end up with premature battery/equipment failure? The Harbor Freight panel is not for me. I don't like amorphous cells and cannot accept dead silence when there are clouds. Thx for the help! Clinton

You can connect your VW panel directly to the 4.5 ah battery without any charge controller. I suspect your VW panel might not have enough voltage to power the amp directly. A solar panel's voltage drops dramatically when you place a load on it. You would probably need to connect two VW panels in parallel to produce sufficient juice. You then risk overpowering your amplifier. Putting a battery in the circuit regulates the voltage and prevents damage. Read here for a good description of running on minimum voltage-http://www.diyaudio.com/forums/showthread.php?postid=1214804#post1214804A 41hz.com amp6basic kit amplifier has built in voltage regulation and is a nice upgrade from the SI T-amp.Ultimately, if you don't want to experiment, but just want solar powered tunes, use a battery in the circuit, and consider adding a second VW panel in parallel for quicker charging.enjoy,Pekar

Thx 4 the reply. Question: Why would your 1.2W panel run the T-Amp and speakers when my 3.2W panel won't? Are my speakers drawing that much more power? This leads me back to the start, thinking about a 10W panel hooked up to a 4ah battery. with charge controller. All these parts add weight, but to reach my goal of plenty of juice for evening / non-sunny times, maybe I have to. I wonder how much of a charge the 3.2W VW panel can give the battery? Or... how long would it take to charge that 4ah battery? cm

Had some of those high cumulus clouds this afternoon, so got to do some interesting testing. Evidently yesterday the sun was getting too low and there was haze. Sunlight wasn't as bright and crisp as high noon. At 3pm today went out again, and if there were no clouds whatsoever, the 3.2W VW panel powered the T-Amp and Polk speakers just fine. Not as loud as with AA batteries, but it was audible and definitely 100% solar powered. When a wisp of cloud came in between, the power dropped enough to clip, then cut out. So your analysis (not enuf power with the 3.2W panel) was correct. But jeepers, was it WAY cool when the tunes were playing on pure sunpower! I've also decided how to set this up: 10W panel, charge controller, 4ah battery. Yeah, it costs more and weighs more, BUT it's gonna be a stable system in different weather conditions and when you want tunes, there is nothing worse than having it cut out. It's also a pretty feeble demonstration to show people or take to a party if it's always cutting out. This will solve all that.

I really like this idea. Now let me ask, would I be able to use powered computer speakers for this project? And can I use the solar panel as well as ac current for this project? And would I still need a 12 volt battery for this? Sure hope someone can help on this project, can't wait to get started. Thanks.

If your speakers have an external 12v. power supply (wall wart), then it should work easily. If the power supply is internal, then it gets more complicated, and I'd recommend starting with something else, or buying the Sonic Impact amplifier. A battery is necessary for a usable system. Dual powered systems are possible.

Great then cause I do have a "wall wart" so I just hook up straight to the power input wires on the board, right ? Also one more question, I was only able to get a larger solar panel such as the one you have on your Delsol system ,think I'll run into any problems with this one? Once again thank you by the way.

If the amp is 12 volt DC, then you should be able to do this. the larger panel shouldn't be a problem. The panel may or may not put out enough power to run the amp directly. Including a battery in the circuit both ensures that the amp gets enough power to run, and protects the amp from the higher voltage the panel puts out. Be aware that you could damage your speakers amplifier, and good luck!

I love the idea of an amplifier powered solely on solar power without batteries. I built my own by using an Altec Lansing XM radio boombox thing and two solar panels from walmart. The basic idea is to buy an mp3/satellite radio docking station with a built in amp. However make sure the amp is class D so it will consume as little power as possible. I found some 2.4watt/130mA solar panels at walmart for $10 each! Now thats cheap! In full sunlight these panels produced 22 volts. At first I was scared I was going to overpower the amp by plugging in the first panel so I connected a 7.5 volt Zener diode in parallel with the power input to ensure that no more than 7.5 volts were applied to the little amp. No sound...Next I connected the second panel in parallel and voila! music from my Ipod started to crank out of the boombox. So in my situation it took two 2.4watt panels in parallel to produce the necessary current to feed the amplifier. However as others have noticed, clouds and shadows cast on the panels will temporarily shut down the amp or cause it to distort. Also it only plays at moderate volume levels because of a lack of current. The zener diode started to get hot so I tossed it and applied the full voltage to the unit with no problems. I had a car audio 1 farad capacitor laying around so I hooked it up in parallel to the panels and it stops the amp from clips and shutting down during periods of reduced light. However, to make the system more practical it would be best to add a sealed lead acid battery and scrap the capacitor. Why waste the energy when it could be stored?

Your best bet is to connect simultaneously with the batteries. My amplifier uses much less power than a conventional amp, so I'm able to run off the small panel directly. I suspect you'll find that this small panel won't put out enough current to power your system. but it will contribute and extend your run time. It will also recharge your batteries(when the stereo is off), but might require a long time in the sun to fully charge them (2-4 days). You're pretty safe in trying this out! have fun.

Yes. You may also consider just making a battery holder that sits under the solar panel, so you don't have to worry about the weather as much. Two solar panels can be joined (parallel) to charge twice as fast, but don't connect them directly to the stereo without batteries in the circuit, as they might put out enough current to damage the amplifier circuit.

:D i love it lol iv made something like this comment it and does the ah matter cuz i used a 12v yuasa 2.1ah battery ??? mine was a moded old amp that worked fine but then started to go dodgy so we chucked it lol hoping to get a t-amp soon for my new virsion x loving the work keep it up (Y)

Unfortunately, those speakers sound like crap. This project can take many forms. The panel you mention will work. The panel I use was chosen for its low cost, and appropriate size for integrating into a portable unit with minimum fuss.

this is an awesome idea! i think i'm going to take it a step further and drop down the weight as much as possible to easily use it for camping and short backpacking trips. i spent all morning looking for components ... i just ordered a pair of bluapunkt thx 352 speakers - small, powerful, and lightweight. I'm going to add ipod charging and line in capability as well as make the case out of carbon fiber.

pretty neat idea... one comment though, the keywords in for searching this instructable... most of them don't have commas after them, so that may be a problem... just thought you should know... have to say though, good use of solar power! I must say I'm surprised that cell will power the speakers!

This is a cool idea. If you want to maximize the effectiveness of this design you will use the most efficient speakers you can find. With found or free speakers this would not be top priority. If, however, you are buying new speakers to use for this you will want to buy the ones with the highest efficiency (sensitivity) rating represented as XXdb @1watt/1meter or XXdb @2.83volts/1meter.

This means that they will play louder with any given amount of power (which is very little in this case) and, as a product of using less power, will drain the batteries more slowly. Because highly efficient speakers are large horn loaded designs (or esoteric transmission line designs) the most efficient speaker you can expect to find in a manageable size is probably in the range of 93db.

In the 1960's Klipsch salesmen would demonstrate their Klipschorn loudspeaker by connecting it to a 9 volt transistor radio and wowing their audience with how loudly it played. This has been my inspiration in most of my audio experimentation. More realistically, You could use the Klipsch Heresy or Cornwall and still have a deafeningly loud system.

Yeah they are pretty well designed speakers even by todays standards. The Heresy would be ideal but still quite a bit larger than the Duals in your photos. Another route to take would be a mono configuration using a dual voicecoil woofer with midwoofers/squawkers side-by-side and tweter horns side-by-side. Because the woofers are the largest, heaviest drivers this would take a bit of weight out of the equation. Since boom boxes are basically mono sources anyway making this in a single narrow column (like an upright rolling suitcase) would not really effect the sound negatively.